CVE-2021-41862: AviatorScript through 5.2.7 allows code execution via an expression that is encoded with Byte Code Engineering

This week

CRITICAL 9.8REMOTEDOWNGRADE

CVE-2021-41862 is a critical-severity flaw (CVSS 9.8) affecting aviatorscript. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

AviatorScript through 5.2.7 allows code execution via an expression that is encoded with Byte Code Engineering Library (BCEL).

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.9% (top 20%)
CISA exploited list	No
Weakness	CWE-74
Published	2021-10-02
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: aviatorscript project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-10-02 00:15 UTCPublished CVE record published
2026-06-17 04:09 UTCUpdated Record last modified

aviatorscript project aviatorscript DOWNGRADE

Affected: >= 5.2.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.2.1

1. Check installed version

apt-cache policy aviatorscript || rpm -q aviatorscript || aviatorscript --version

2. No fixed release: DOWNGRADE to a release before 5.2.1 (Debian / Ubuntu)

apt-cache madison aviatorscript sudo apt install aviatorscript=<VERSION_BEFORE_5.2.1> sudo apt-mark hold aviatorscript

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list aviatorscript sudo dnf downgrade aviatorscript-<VERSION_BEFORE_5.2.1> sudo dnf versionlock add aviatorscript

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-41862?

aviatorscript: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-41862 being exploited?

CVE-2021-41862 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-41862 affect?

CVE-2021-41862 affects aviatorscript. Severity is critical (CVSS 9.8). AviatorScript through 5.2.7 allows code execution via an expression that is encoded with Byte Code Engineering Library (BCEL).

How urgent is CVE-2021-41862?

Priority 64/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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